Tremper K K, Hufstedler S M, Barker S J, Zaccari J, Harris D, Anderson S, Roohk V
Crit Care Med. 1986 Mar;14(3):231-3. doi: 10.1097/00003246-198603000-00013.
A new device has been developed to estimate continuously and noninvasively cardiac output from the thoracic electrical bioimpedance (CObi). CObi was compared to cardiac output by thermodilution (COtd) in five anesthetized dogs. Blood pressure, blood volume, and blood flow were manipulated by hemorrhage and infusions of sodium nitroprusside and phenylephrine. These data were used to determine the correlation between CObi and COtd under conditions of hypotensive normal flow and normotensive low flow, as well as during hemorrhagic shock and resuscitation. The CObi device was calibrated in vivo to COtd for each dog at the beginning of each experiment. CObi had a significant positive correlation with COtd throughout the experiments (r = 0.84, slope = 0.91, intercept = 0.55, p less than 0.01), and CObi predicted COtd with a standard error of the estimate of 0.81 L/min. Neither heart rate nor mean arterial pressure was significantly correlated with COtd or CObi. During severe hemorrhagic shock, CObi could not determine cardiac output in two of the dogs when COtd averaged 1.7 L/min. These data indicate that CObi is a blood-flow related variable that can be monitored continuously.
一种新装置已被研发出来，用于通过胸电阻抗连续无创地估计心输出量（CObi）。在五只麻醉犬中，将CObi与热稀释法测得的心输出量（COtd）进行了比较。通过出血以及输注硝普钠和去氧肾上腺素来控制血压、血容量和血流量。这些数据用于确定在低血压正常流量和正常血压低流量条件下，以及在失血性休克和复苏期间CObi与COtd之间的相关性。在每个实验开始时，针对每只犬在体内将CObi装置校准至COtd。在整个实验过程中，CObi与COtd具有显著的正相关（r = 0.84，斜率 = 0.91，截距 = 0.55，p小于0.01），并且CObi预测COtd的估计标准误差为0.81 L/分钟。心率和平均动脉压与COtd或CObi均无显著相关性。在严重失血性休克期间，当COtd平均为1.7 L/分钟时，CObi无法测定两只犬的心输出量。这些数据表明CObi是一个与血流相关的变量，可进行连续监测。
